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Home > Business > Company News > Photometric & Optical Testing Services LLP Offers Large 3m Integrating Sphere Measurement
News-Spot | Business News | Feb 12, 2013

Photometric & Optical Testing Services LLP Offers Large 3m Integrating Sphere Measurement

Photometric & Optical Testing is now able to offer measurement services using a 3m diameter integrating sphere. The bigger and more powerful the light source, the bigger the sphere needs to be!

3m Sphere With the addition of this new capability, no job is too big for us! Photometric Testing is the only independent lighting test laboratory in the UK which is able to offer measurements in a properly designed 3m integrating sphere, which means that we can now verify the performance of even the very biggest and intense lamps and luminaires quickly and accurately.

The new large sphere service employs a state-of-the-art 3m Labsphere Illumia® integrating sphere that fully conforms to the exacting requirements given in IES LM-79-08 and in BS EN 13032. The sphere provides for accurate 2pi and 4pi measurements of spectral radiant flux, luminous flux, scotopic flux, S:P ratio, CIE chromaticity, correlated colour temperature (CCT) and colour rendering index (CRI, RA).

We've not cut any corners with our integrating sphere. Non-spherical integrators (typically cubes or other geodesic shapes) suffer from an uneven luminance distribution, a problem compouned when used to measure directional light sources - and let's not forget that solid state lighting is nothing if not HIGHLY directional! So our 3m sphere will give accurate and repeatable results even with narrow beam angle spotlights and downlighter fittings. Moreover, our sphere is coated with Labsphere's proprietary 98% reflectance Spectralflect sphere paint. Compared to lower reflectance coatings, our integrating sphere is highly non-directional, meaning you get the right lumen reading regardless of the size, position and beam shape from the light source under test. We perform auxiliary correction as standard to ensure that the self absorption of the device under test is corrected, while our high speed array spectrometer gives near instantaneous readings of both photopically and scotopically-weighted flux.

The 3m sphere service compliments our existing 0.5m and 1m sphere service and goniophotometric service for the generation of photometric data files in standard .ies and .ldt formats. Photometric Testing also offers design consultancy, on-site photometric and light nuisance evaluations as well as photobiological safety testing and training courses in photometry and in photobiological safety.

For more information on any of Photometric & Optical Testing Services' services - including the large sphere service - please visit